An occupational psychologist investigated whether the ambient temperature of a workspace influences perceived mental fatigue after a prolonged cognitive task.
They conducted a repeated measures design experiment using a climate-controlled laboratory. In Condition A, participants completed a 45-minute analytical coding simulation in a room kept at a warm temperature of 27∘C27^\circ\text{C}27∘C. Immediately after finishing, they rated their perceived mental fatigue on a scale of 1 ('completely energized') to 15 ('physically and mentally exhausted'). Five days later, the same participants returned to complete a different, but structurally identical, 45-minute analytical coding simulation in the same room, this time kept at a cool temperature of 17∘C17^\circ\text{C}17∘C (Condition B), and rated their fatigue using the same 1–15 scale.
The data collected is shown in the table below:
| Participant | Condition A (Warm, 27∘C27^\circ\text{C}27∘C) | Condition B (Cool, 17∘C17^\circ\text{C}17∘C) |
|---|---|---|
| 1 | 14 | 6 |
| 2 | 11 | 3 |
| 3 | 8 | 9 |
| 4 | 13 | 14 |
| 5 | 15 | 5 |
| 6 | 10 | 7 |
Outline one reason why the reliability of the data collected in this study could be low.
